Voltage regulator



Jafn. 13, l948- J. F. KovALsKY 2,434,569

VOLTAGE REGULATOR Filed Feb. 22, 1945 2 Sheets-Sheet 1 wlTNEssEs:

Jan.- 13, 1948. J. F. KovALsKY v 2,434,569

VOLTAGE REGULATOR ATTORNEY gua/ff Patented Jan. 13, 1948 VOLTAGEREGULATOR Joseph F. Kovalsky, Turtle Creek, Pa., assignor to'Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application February 2z, 1945, serial N.\,579.e4s

c claims. (ci. aol-51) compact unit; The simplest self-contained unit Iregulator is that which uses an alternating-current magnet and operatesdirectly from the altermating-current outputV of the generator withoutthe use of intermediate rectiilers. In such altermating-current magnetictype of regulators, it has been found that errors occasioned by changesin frequency or by vibration caused by the sinusoidal current usuallyprevent the satisfactory use of alternating-current regulators forcingthe user to employ a direct-current magnetic type of regulator and theaccompanying equipment necessary to convert the alternating current tounidirectional current.

An object of this invention is the provision of a rugged, compactregulator of the alternatingcurrent magnetic type.

Another object of this invention is the provision of analternating-current magnetic type of regulatorwhich inherentlycompensates for change in frequency. x

A more specific object of this invention is to provide for compensatingfor frequency changes and vibration in an alternating-current magnetictype of regulator, the regulator being constructed as a compact unit andbeing capable of use in, any mounted position. L

Other objects of this invention will become apparent from the followingdescription when ftaken in conjunction with the accompanying drawings inwhich:

Figure 1 is a top plan view, with the cover removed, of a regulatorembodying the teachings of this invention.

Fig. 2 is a side elevational view, with parts removed, of the regulatorshown in Fig. 1.

Fig. 3 is a bottom plan view of part of the regulator shown in Fig. 2but removed from the.

housing.

Fig. 4 is a fragmentary end view of part of the housing mounting andterminal block of the regulator shown in'Fig. 2.

Fig. 5 is a view taken along the line V-V of Fig. 4.

Fig. 6 is 'a diagrammatic showing of a part of the regulator.

Fig. 7 is a. representation of the impedances and resistance oftheapparatus shown in Fig. 6.

Fig. 8 is a diagrammatic showing of another part of the regulator.

Fig. 9 is a representation of the impedances and resistance of the partof the regulator shown in Fig. 8.

Fig. 10 is a representation of the relation of the current and voltagein the parts of the regulator shown in Figs. `6 and 8 as theyco-operate, and v Fig. 11 is a schematic diagram of apparatus andcircuits illustrating the regulator of this invention `as used in aregulating system.

Referring to the drawings and in particular to Figs. 1 and 2 thereof,this invention is illustrated as comprising avoltage regulator I0 havinga mainhousing I2 for containing the main movable\parts thereof and anauxiliary housing I4 for containing a resistor unit, b oth housingsbeing secured together and mounted on. but spaced from, a suitable basemember I6.

The main housing I2 is formed of metal being drawn or otherwise formedto have integral side walls I8 and bottom 2D, a removable cover 22 beingdisposed to enclose the cavity formed therein. The bottom 20 is providedwith a centrally disposed aperture 24 through which leads may extend asdescribed hereinafter. The upper edge of one of the side walls I8 is cutaway as at 2B for accommodating certain leads referred to hereinafterand suitable inwardly extending brackets 28 'are secured to the innersides of three of the side walls at a predetermined level within thecavity.V Adjacent the fourth side wall is disposed a capacitor unit 30which is mounted on the bottom 20 as by means of the studs 32, theterminals when necessary. As illustrated in Figs. 1 and 3,

the baflie plate `38 is so cut as to fit around the capacitor unit 30and to leave space between the edges of the plate 38 and the side wallsto permit circulation of air within the main housing. The plate 38 isalso provided with a somewhat centrally positioned aperture 42, thepurpose of which will be explained hereinafter.

As viewed in Figs. 1 and 2, the plate 38 carries a switching mechanism44 on its upper surface at one side of the aperture 42. The switchingmechanism illustrated comprises a plurality of long thin conductingmembers 46 which are insulated at one end from each other but securelyclamped together in an insulating block 48 secured to the plate 38 bythe screws 50, the other ends of the conducting members 46 havingcontact buttons or members 52 thereon and being self-biased to seatspaced apart against an angular stop member 54 which is also secured tothe plate 38. A driver member 56 of insulating material, the mounting ofwhich will be explained more fully hereinafter, is disposed to actuatethe conducting members 46 in a progressive manner, a spring 58 beingmounted on a bracket 60 carried by the plate 38 for biasing the drivermember 56 against the conducting members.

The operating mechanism for actuating the driver member 56 is moreclearly shown in Fig. 3

,and is mounted on the under side of the plate 38 as illustrated in Fig.2. As illustrated, the operating mechanism comprises two positionallyopposed electromagnets 62 and 64 which are secured to the plate 38 bybrackets 66 and 68, respectively, the electromagnets being structurallysimilar and preferably having substantially identical electricalcharacteristics. The electromagnets 62 and 64 comprise the windings 10and 12, respectively, and the movable core members 14 and 16,respectively. As illustrated, the electromagnets are carried on theunder side of the plate 38 in spaced relation and in the reversedirection to each other so that when energized the core members 14 and16 tend to move in opposite directions in substantially parallel pairs.In order to prevent stray fluxes, disk members 18 are disposed at eachend of the electromagnets.

As it is proposed to simultaneously energize the electromagnets 62 and64, the core members 14 and 16 are coupled by a connecting arm 80 whichhas angular end portions secured to the core members. The centralsection of the connectinar arm 80 is secured to a vertical arm 82 asviewed in Fig. 2 by the rivets 84 near the lower end ofv the verticalarm 82, the upper end of which projects through the aperture 42 and issecured by the screw 86 to the driver member 56.

In order to pivotally support the connecting arm 80 and consequently thedriver member 56, a downwardly projecting bracket 88 is secured to theplate 38 by screws 00. Spaced apart on each side of the connecting arm80 are leaf springs 82 and 84, each of which has one end thereof securedto the bracket 88 by rivets 96, the other ends of the leaf springs 82and 84 being secured to the arm 82 by the rivets 98 and |00,respectively. In f ing members 46 to maintain the driver member 56 in agiven position in accordance with the energization of the electromagnets62 and 64, a biasing spring |06 is disposed with its one end secured toan adjustable screw member |08 carried by the end of the connecting arm80 secured to the core member of electromagnet 64, the other end of thebiasing spring |06 being secured through a bolt I|0 to an end of abimetal leaf |I2, the other end 4 of which is secured to the downwardlyprojecting bracket ||4 carried by the plate I8. The bimetal leaf I2aiIords temperature compensation for the operating mechanism by varyingthe tension of the biasing spring |06 in accordance with changes intemperature.

With the electromagnets 82 and 64 secured to the plate 38 as described,and the driver member 56 pivotally carried by the connecting arm 80 toactuate the switching mechanism 44 carried on the other side of theplate 38, the assembled operating mechanism is readily positioned in thehousing with the leads I6 and I8 of electromagnet 62 and leads |20 and|22 of electromagnet 64 extending outwardly through the aperture in thebase of the housing. Leads |24 constituting an extension of theconducting leaf spring members 46 and which are insulated from eachother by suitable strips |26 of insulating material extend outwardlythrough the cut away section 26 in the side wall.

As illustrated in Figs. 1 and 2, the auxiliary L' housing I4 is carriedby one of the side walls of housing I2 and encloses a pile resistor unit|28. In order to support the pile resistor unit |28, end plates |30 and|32 formed of substantially U- shaped channel members are positionedlacing each other, one of the flanges of each of the plates |30 and |32terminating in an aligned downwardly extending leg |34, respectively,which are secured to a tie bar |38 by recessed screws |40 to maintainthem in spaced relation. Extending through the end plates |30 and |32are supporting tie bolts |42, |44, |46 and |48 which are so spaced as toholdV the disks of the resistor unit |28 in assembled relation, it beingnoted that the leads |24 extend downwardly in contact relation betweenthe disks of the resistor unit.

Pressure plates |50 and |52 are disposed at opposite ends of the stackof disks and are held in pressure applying position by the rivets |54and |56, respectively, the heads oi' the rivets seating in grooved outdepressions in the faces of the pressure plates, the tie bolts |42, |44,|46 and |48 also functioning to aid in positioning the ypressure plates.A tie bar |58 also extends between the other flanges of the end plates|30 and |32 being welded thereto and aiding in supporting the stack ofdisks of the resistor unit |28. The Housing I4 which is open at thebottom and back, and is preferably of a screen material, is positionedover the assembled resistor unit and removably secured to the outerflanges oi end plates |30 and |32 by screws |60.

In order to secure the assembled resistor unit to the main housing I2, abar |62 is positionally welded to the side wall of the housing I2 andthe tie bar |38 is secured thereto by spaced screws |64 as more clearlyshown in Fig. 4. In this position the leads |66 and |68 at the ends ofthe resistor unit |28, and which are secured to the leads |24 at theends of the stack as viewed in Figs. 1 and 2, depend through the openbottom of the housing I4.

The housings I2 and I4 with the operating mechanism therein as describedare resiliently mounted on the base member I6 by means of four spacedstuds |10 extending through the base of the main housing I2 andresilient bushings |12 disposed between the housing I2 and the basemember I6. The resilient bushings |12 are of suiilcient size tov permitthe leads from 'the electromagnets 82 and 64 and lead |14 to theterminal 36 of the capacitor to extend between the bottom ofl the mainhousing I2 and the base I8 to a terminal block |16 mounted at the end ofthe base beneath the housing |4.

The terminal block |16 consists of a strip |18 of insulating materialcarrying four spaced terminals |80, |82, |84, and |86 suitably rivetedthereto for receiving the leads of the regulator.

vAs shown in the schematic diagram, Fig. 11, the 'resistor leads |66 and|68 are secured to the y outer terminals |86 and |80, respectively,wherenected in series circuit relation with each other and the seriesconnected elements are connected in parallel circuit relation with theyother electromagnet 64.

The insulating strip |18 carrying the terminals extends across the endof the regulator and is maintained in an angular position on spacedsupports. The supports are formed of a hollow insulating post |80 and abase member |92 each havingfl` a complementary angular surface forseating on opposite si es of the base member I6,

vthe strip |18, post |9 and member I 92being held in assembled relationby screws |84, the end of which is rin threaded engagement with themembeixl 92.

Referring to Fig. 11,"`th`e"regulator i0 is illustrated `as connected ina system for regulating Ythe voltage-of an alternating-current generator|96. As illustrated, th generator |96 consists of an armature* windingconnected by the-circuit breaker200 to deliver. power to a polyphasesysterrr. representedhy conductors 202, 204 Rand the regulatorI0`connected vin circuit reation thereto for controlling the excitation*of the exciter. The\terminals |82 and |84 ofthe. regulator I0 areconnected to the terminals of the secondary winding of. a potentialtransformer 2|8,\the

primary windingof which is\.c`onnected\ across-a phase' of theconductors supplied by `gcnerator |96 whereby the opposed electromagnet62 and 64 of the regulator |0 are disposed to be simultaneouslyenergized a d any variation in the voltcurrent I1 and remains constantwith constant voltage and constant frequency o'f sinusoidal wave form.

However, as is well known, the frequency changes when the speed oftheprime mover changes due to load changes?, Thus, since the reactance XLis a function of 21r`fL, the reactance XL will increase when thefrequency ,f increases and will decrease with a decrease in thefrequency. Then from Equation l it is seen that theimpedance X1 willincrease with an increase in the frequency with the result that withconstant voltage E1 across terminals |82 and |84 the current I1 willdecrease and consequently the flux .and pull of electromagnet 64 willdecrease.

As stated hereinbefora the electromagnets 62 `and 64 are structurallysimilar and preferably have substantially identical electricalcharacteristics, but are mounted in opposed relation. As opposed toelectromagnet 64, 'the electromagnet 62 is also connected in series withthe capacitor so that the circuit for theY electromagnet 62 may beillustrated as in Fig. 8 being composed of the inductive reactance X1.of winding 10, the resistance R of the winding, and the capacitivereactance Xo. In practice, the capacitive reactance Xc is'generallyproportioned so that it is age across the vconduc ors suppliedby thegenerator |96 has a-direct effect on `the\operation of the regulator.

In order to better understand tl1\operation of Y the regulator `|0 whena variationin the alternating-current voltage occurs, reference may behad to Figs. 6 through 10. Fig. 6 is a representa- Y tion ofelectromagnet64 connectedtolbeupplied from the alternating-currentcircuit and is shownV to comprise..,thevresistance R of winding 12 and'the reactance X1. of the winding;H Thus the impedance Z1 of theelectromagnet 64 is as shown in Fig. 1 since equal to two timesthe valueof the inductive reactance XL and as the impedance Z2 of the circuit ofelectromagnet 62 may be given as the impedance Z2 may be illustrated asin Fig. 9

of the drawing in which the combined reactance X=XoXL or a capacitivereactance.

As the capacitive reactance X is a function of it will be appreciatedthat the capacitive reactance will increase with a decrease in frequencyor decrease with an increase in frequency and from Equation 2, itfollows that the impedance Z1 will then decrease witha decrease infrequency and that the flux and resulting magnetic pull of .whereby thenet result is that the total magnetic Y pull remains unchangedvaryingonly with a change in the voltage ofthe machine to be regulated.. Thusthe regulator ||l is unaffected by changes in frequencyof thealternating-current supply.

From Figs. 7 and 9', it isseen that the impedance Z1 and the imp edanceZ2 are 90 apart.

Since the current I1 is in phase with resistance R and is 45 out ofphase with the voltage E1, and

magnet is sinusoidal, the wave or force pulsates from zero to maximumtwo timesy per cycle on each electrornagnet.` Since, as shown in Fig.10, the currents I1 and I2 are out of phase by an angle of 90, the iiuxwill also-be shifted 90 and the force will pulsate on the connecting arml between the electromagnet B2 and 84 with the equivalent oi' four timesper cycle. By properly balancing the pull of the main spring IUI for themass of the moving parts of the regulator, the vibration is reduced to aminimum to give a required sensitivity to the regulator. In some casesit is desirable to add weights (not shown) to the connecting arm toincrease the mass and thereby effect damping to permit an increase inthe frequency range and still maintain a sensitive 0peration.

With the foregoing description, the operation of the regulator |0 isapparent. For example, in the system illustrated in Fig. 11 assume thatthe motor 2|2 is driving the exciter 2|0 and generator |96 to supply agiven load at a constant voltage. Under such circumstances, theelectromagnets G2 and 64 are so energized that a number of the leaves 46are actuated away from the sloped stop 54 to shunt a number of sectionsof the resistor unit |28 from the eld winding cirnets E2 and 64 aredeenergized proportionallywhereby the main spring |06 actuates theconnecting arm 80 about its pivot tofeffect a movement of the drivermember 56 to bias additional leaves 46 away from the stop 54 to shuntadditional sections of the resistor unit |28 and thereby increase theexcitation of the lexciter 2|0 to effect an increase in the excitationof the generator |96 to increase the voltage across the conductors tothe predetermined constant voltage.

If, on the other hand, the change in voltage impressed on thetransformer 2|8 is an increase, then the energization of the windings ofelectromagnets 62 and 64 is an increase to effect a movement of theconnecting arm 80 about its pivot to actuate the driver member 56torelease additional leaves 46 and connect additional sections circuit,it is apparent that the regulator I0 is unaffected by any change infrequency of the alternating-current voltage supplying the regulator.Although, as stated hereinbefore, it is preferred to proportion thecapacitive reactance of the capacitor 30 to two times the value of theinductive reactance of the winding of the electromagnet, it is, ofcourse, understood that variations in the proportioning may be had whereit is desired to compensate for a drop in speed of the prime mover.

For example, the capacitor 3d can be so proportioned that the impedanceZ2 is so altered that there is a slight unbalance in the total pull onthe connecting arm to make up for the droop in speed and consequentlythe change in frequency when load is applied. This droop in speed ischaracteristic of the machine or generator when load is applied it beingnoted that the speed also increases somewhat when the load is removed.Small machines usually have a permissible droop of plus or minus 3%. Theregulator described can therefore be made to compensate for theb voltagewhich results in droop and can even be made to compensate more thanrequired for fiat voltage regulation and thus give a rise in voltagewith increased load as required in some applications by correctlyproportioning the capacitor 30. Thus overcompensation may be had byproportionin'g the capacitive reactance of the capacitor 30 so that itis greater than twice the value of the inductive reactance of theelectromagnet.

The regulator ill-is compact in size but rugged in construction. It isvery sensitive having an exceedingly smooth operation by reason ofincreasing the pulsations applied to the connecting arm between theopposed electromagnets. As the regulator can be energized directly froman 8.1- ternating-current source without the use of 1ntermediaterectiilers, the simplification of apparatus required is apparent:Because of its ruggedness, it can be used in any position withoutailecting its operation.

I claim as my invention:

1. In a voltage regulator for an alternatingcurrent dynamoelectricmachine having a variable frequency, in combination, contact members.disposed for movement to and from contact mak-*f ing positions. adrivermember disposed to be actuated to effect the movement of thecontact members, a pair of electromagnets having substantially identicalelectrical characteristics, each of the electromagnets having a windingand a core member, the windings being connected in parallel circuitrelation with each other disposed to be simultaneously and directlyenergized by alternating current in accordance with the operation of thedynamoelectric machine, theelectro` magnets being disposed in spacedrelation and positioned in the reverse direction to each other wherebythe core members move in substantially parallel paths but in oppositedirections when the windings are simultaneously energized, a connectingarm pivotally disposed between and connected to the spaced core members,the connecting arm also being connected to the driver member to effect amovement thereof as the arm is plvotally Y moved, and a capacitorconnected in series circuit with only one of the windings, each of thewinding circuits comprising a non-resonant circuit, the capacitorfunctioning upon a change in frequency of the dynamoelectric machine tomodify the effective impedance of the one winding circuit whereby thechange in the magnetic pull of the one winding occasioned by the changein frequency is in opposition to the change in the magnetic pull of theother winding occasioned by the change in frequency.

2. In a voltage regulator for an alternatingcurrent dynamoelectricmachine having a variable frequency, in combination, an adjustableresistor, means disposed for movement to adjust the resistor, a pair ofelectromagnets having substantially identical electricalcharacteristics, each oi' the electromagnets having a. 4winding and acore member, the windings being connected in parallel circuit relationwith each other disposed to be simultaneously and directly energized byalternating current in accordance with the operation oi' thedynamoelectric machine, the electromagnets being disposed in spacedrelation and positioned in the reverse direction to each other wherebythe core members move in substantially y parallel paths but in oppositedirections when the windings are simultaneously energized, a

connecting arm pivotally disposed'between and y connected to the coremembers, the connecting arm also being connected to the adjusting meansto eiect an adjustment of the resistor as the arm is moved, and acapacitor connected in series circuit with only one of the windings,each of the winding ycircuits comprising a non-,resonant circuit, thercapacitor functioning upon a change in y frequency fof vthedynamoelectric machine to of the dynamoelectric machine to maintain alub modify the etiectiveimpedance 'of the one windf n ing circuitwhereby the change in the magneticf pull of the one winding occasionedbythe change U in frequency isin opposition tothe change in thefmagnetic pull of the other winding occasioned by.r

the change in frequency.

' 3. In a voltage regulator current dynamoelectric machine having avariable frequency, in combination, a plurality of contact membersdisposed for'movement to andfrom contact making positions, a drivermember disposed to be actuated to effect the movement of the contactmembers, a pair of electromagnets having substantially identicalcharacteristics, each of the electromagnets having a winding and a coremember, the windings being connected in stantially constant totalmagnetic pull on the core members variable only with changes in thevoltage of the dynamoelectric machine.

5. In a voltage regulator for an alternatingcurrent dynamoelectricmachine having a variable frequency, in combination, a plurality ofcontact members disposed' for movement to and from contact makingpositions, a driver member disposed to be actuated to effect themovement of the contact members, a pair of electromagnets havingsubstantially identical characteristics,

each of the-electromagnets having a winding and V a core member, thewindings having substantially equal values' of` inductive reactance andbeing connected in parallel v.circuit relation with each fo'r analternating` parallel circuit relation with each other disposed Y to besimultaneously and directly energized by alternating current inaccordance withv the operation ofthe dynamo-electric machine, the elec#tromagnets being disposed in spaced relation and positioned in thereverse direction to each otherv non-resonant circuit, the windingshaving the capacitor in circuit with the one windingco-operating upon achange in frequency of the dynamoelectric machine to maintain asubstantially constant total magnetic pull on the core members variableonly with changes in the voltagev oi' the dynamoelectric machine.

4. In a voltage regulator for an alternatingcurrent dynamoelectricmachine having a variaother, the windings beingdisposed to besimultaneously and directly energized by `alternatingcurs v rent inaccordance with they operation of the. dynamoelectric machine, theelectromagnets b'eing disposed in spaced relation and positioned fin thereverse directions'toeach other whereby the core members move inparallel pathsbut in opposite directions when the windings aresimultaneously energized, a connecting arm pivotally disposed betweenand connectingv the core members, the connecting arm also beingconnected to the driverk member to effect a movement thereof as :the armis moved,.and a capacitor connected in `series circuit with only one ofthewindings, the

the capacitor having a capacitive reactance at a predetermined frequencyof the dynamoelectric machine equal to two times the inductive reactanceof the winding with which it is connected in series circuit, the windinghaving the capacitor in circuit therewith co-operating with the otherwinding upon a change in frequency of the dynamoelectric machine fromthe predetermined frequency to maintain a substantially constant totalmagnetic pull on 'the core members variable only with changes in thevoltage of the dynamoelectric machine.

6. In a voltage regulator for an alternatingcurrent dynamoelectricmachine having a varia- `ble frequency, in combination, an adjustableresistor, means disposed for movement to adjust the resistor, a pair ofvelectromagnets having sub-` ble frequency, in combination, anladjustable resistor, means disposed for movement to adjust theresistor, a pair of electromagnets having substantially identicalelectrical characteristics, each of the electromagnets having a windingand a core member, the windings being connected in parallel'circuitrelation with each other disposed to be simultaneously and directlyenergized by alternating current in accordance with the operation of thedynamoelectric machine, the electromagnets being disposed in spacedrelation and positioned in the reverse direction to each other wherebythe core members move in parallel paths but in opposite directions rwhenthe windings are simultaneously energized, a connecting arm pivotallydisposed between and connected tothe core members, the connecting arm`also being connected to the adjusting means to effect an adjustment ofthe resistor as the arm is moved, and a capacitor connected in seriescircuit with only one of the windings, each of the winding circuitscomprising a non-resonant circuit. the windings stantially identicalelectrical characteristics, each of the electromagnets having a windingand a core member, the windings having substantially equal values ofinductive reactance and being connected in parallel circuit relationwith each other disposed to be simultaneously and directly energized byalternating current in accordance with theoperation of thedynamoelectric machine, the electromagnets being disposed in` spacedrelation and positioned in the reverse direction to each other wherebythe core members move in parallel paths but in opposite directions whenthe windings are simultaneously energized, a connecting arm pivotallydisposed between and connected to the core members, the connecting armalso being connected to the adjusting means to effect an adjustment ofthe resistor as the arm is moved, and a capacitor connected in seriescircuit with only one ofthe windings, the capacitor having a capacitivereactance at a predetermined yfrequency of the dynamoelectric machineequal to twotimes the inductive reactance of the winding with which itis connected in series circuit, the winding with the capacitor in seriescircuit therewith cooperating with the other winding upon a change infrequency of the dynamoelectric machine from the predetermined frequencyto 11 pull on the core members vsrinbls only with changes in the voltageof the dynamoelectrlo ml- UNITED STATES PATENTS chine. Number Name DateJOSEPH F. KOVALBKY. s 2.008.057 Bohn Juv 16' 1935 2,131,424 Bechbergeret al. Sept. 27, 1938 REFERENCES CITED e 2,309,487 e van c. WarringtonJan. ze, 1943 The following references are of record 1n the 475,514McElroy May 24. 1892 111e o1' this patent: 682,332 Mehlis Sept-10, 1901

